The gutter system of a swimming pool is one of its most important components, and its design is determinative of many of the characteristics of the pool. However, what constitutes good gutter system has long been a perplexing problem in much dispute. What is recognized is that a gutter system must provide an adequate surge flow capacity, especially when the pool is filled with swimmers, and it should not flood when a large group of swimmers enters the pool. It should also provide good surge and wave quelling capacity. Its ability to cope with surges and waves produced by swimmers is quite important to the competitive qualities of the swimming pool.
A problem related to gutter design is the removal of surface dirt. Some types of gutter system are intended to provide a skimming action, but it has generally been conceded that the most efficient type of skimming action is provided by the scum gutter type of pool, and on all pools over 1,600 square feet in area, scum gutters are provided as a matter of course. In fact, in some states, surface skimmers are not permitted.
One type of swimming pool with a perimeter skimming gutter and retaining wall provides for flow of water over the top of the gutter wall into the gutter trough at all times. Such a gutter system is described in U.S. Pat. No. 2,932,397 to Ogden dated Apr. 12, 1960. Another and older design appears in U.S. Pat. No. 1,797,397 to Booraem dated Mar. 24, 1931. Such a gutter system provides an efficient skimming action under normal flow conditions, but as soon as swimmers enter the pool, or a heavy surge or wave action is encountered, the additional flow of water over the top of the gutter tends to flood the gutter, after which skimming action is lost until the water can be drained away, and in fact some of the dirt already in the gutter may be washed back.
In an attempt to alleviate such a condition, a modification of the Ogden gutter system has been proposed in U.S. Pat. No. 3,363,767 to Ellis dated Jan. 16, 1968, incorporating a plurality of skimmer openings spaced around the gutter at a lower level than the top of the gutter. In this gutter system, when the pool is not in use, the skimmer weir is opened and skimming is obtained via the openings into the gutter. When the pool is in use, the skimmer weirs are closed, but the water level is held down below the lip of the gutter, providing a certain in-pool surge capacity, and avoiding a flooded gutter condition at the time of flow surges. However, when the pool is in heavy use and there is considerable wave or surge action over the top of the gutter, surface contaminants washed into the gutter may still be washed back into the pool.
U.S. Pat. Nos. 3,668,712 and 3,668,714, issued Jun. 13, 1972 to Baker, provide perimeter skimming gutters and retaining walls for swimming pools which permit an adequate skimming action at all times and which provide an adequate surge capacity when the pool is in use without the possibility of the flooding of the gutter or of the washing of dirt in the gutter back into the pool.
This is accomplished in Baker '712 by combining a plurality of narrow, elongated, substantially horizontally disposed openings which are open at all times in the retaining wall disposed about the perimeter of the swimming pool, with the peripheral gutter conduit arranged to receive water spilling over the top of the retaining wall when the flow capacity of the elongated openings is exceeded. The elongated openings can be arranged to feed water into the main gutter conduit, or into a separate second gutter conduit keeping the two water flows completely separate and thereby retaining the dirt skimmed off the top of the pool in the second conduit and avoiding the hazard of this dirt being washed back into the pool in the unlikely event of the first gutter conduit being flooded during wave actions or surges. In this gutter system, the water level in the pool is normally maintained at the level of the skimmer openings in the gutter.
In Baker '714, the perimeter skimming gutter comprises a first gutter conduit for disposition about the perimeter of a swimming pool adapted to carry water at a level below a predetermined level of water in the swimming pool; a retaining wall on the pool-side of the first gutter conduit, over the top of which wall water may flow from the pool into the first gutter conduit; and a second gutter conduit in fluid flow connection with the first, such fluid flow connection entering the first gutter conduit at a level below the top of the retaining wall but above a predetermined maximum level in the first gutter conduit to drain off water from the first gutter conduit thereby precluding the level of water in the first gutter conduit from reaching the top of the retaining wall.
U.S. Pat. No. 3,668,713, issued Jun. 13, 1972 to Baker, provides a fluid flow and/or fluid pressure responsive gate weir for swimming pools, comprising in combination: a weir support; a fluid flow passage in the support; a gate member pivotally mounted in the support across the passage for movement between flow-open and flow-closed positions; a gate controller disposed to encounter a fluid flow through and/or fluid pressure in the passage above a predetermined minimum, and responsive to such flow and/or pressure to pivot the gate member from a flow-open towards a flow-closed position; and means arranged to retain the gate member in the flow-open position under normal conditions of fluid flow and/or fluid pressure through the weir passage and the permit pivotal movement of the gate members towards a flow-closed position under excessive fluid flow and/or fluid pressure continues. Means can also be provided to return the gate member to the flow-open position when such excessive flow and/or pressure subsides, and/or returns to normal.
U.S. Pat. No. 3,815,160, issued Jun. 11, 1974 to Baker, provides a nonflooding perimeter skimming gutter and retaining wall for swimming pools including: a first gutter conduit for disposition about the perimeter of a swimming pool and adapted to carry water at a level below a predetermined level of water in the swimming pool; a retaining wall on the pool-side of the first gutter conduit over the top of which wall a skimming flow of water may run from the pool into the first gutter conduit; a second gutter conduit within a peripheral wall below the first gutter conduit and adapted to carry water at a level above a predetermined level of water in the first gutter conduit; and a fluid flow connection between the two gutter conduits at such level and below the top of the retaining wall to allow water to flow from the first gutter conduit into the second gutter conduit whenever the water level in the first gutter conduit reaches the fluid flow connection, thereby inhibiting filling of the first gutter conduit appreciably above such level.
In the twin gutter structures provided in these patents, the two gutters are separate and of fixed dimensions. While the gutters can be interconnected at a number of locations, flow therebetween is normally not possible until one or the other reaches a predetermined overflow level. This is highly desirable in most circumstances, but on occasion a single gutter of large capacity may be preferred and in the fixed-in-place structures of the type described above, this is impossible.
In accordance with U.S. Pat. No. 4,050,104, issued Sep. 27, 1977 to Baker, a twin gutter system is provided in which the twin gutters can be kept separate or combined in one, as desired, by forming the two gutters with at least one common wall, of which at least a portion thereof can be removed. This feature can be applied in any of the twin gutter systems of U.S. Pat. Nos. 3,688,712; 3,668,713; 3,668,714; and 3,815,160, with or without a skimming function as desired. The common wall can be all or part of a side wall, an end wall, a bottom wall, or a corner wall of the gutters.
In all of these gutter systems, the open gutter conduit or gutter trough is intended to receive and carry off floating debris from the surface of the pool, as well as suspended dirt and any similar contaminants, and such material after falling into the gutter is flushed to a filter and removed to keep the gutter in proper functioning order. Gravity flow along the gutter can be relied upon for flushing but often gravity generates water flow that is too slow to provide adequate flushing and cleansing of the gutter trough.
It has therefore been proposed to supplement the cleansing of the gutter trough by gravitational water flow in various ways. For example, Ogden '397, referred to above, discloses valved jet sprays arranged to spray within in the gutter trough when cleansing of the gutter trough is desired. Patterson U.S. Pat. No. 4,059,856, issued Nov. 29, 1977, provides a swimming pool gutter including a combined conduit and a sealed filtered water inlet conduit at the bottom of the gutter conduit. The gutter is formed from two sheet metal members joined by two exposed welds to form a deep-walled gutter capable of accommodating water surges and waves without flooding and having a sealed filtered water inlet combined therewith. Mounted on and spaced along the filtered water inlet conduit are spray nozzles as shown in the embodiments of FIGS. 3 and 4. These spray nozzles communicate through the conduit wall and provide for the distribution of a fine, high pressure spray into the open gutter trough and are directed to provide a continuous flush of filtered water within the gutter trough to continuously wash dirt and debris therefrom.
Notably, in both Odgen '397 and in Patterson '856 the water spray is provided in the open gutter conduit or gutter trough for cleansing of the gutter by direct application of the jet spray within the open gutter conduit. An alternative approach to this direct application of water spray within the open gutter conduit or gutter trough is disclosed by Patterson U.S. Pat. No. 4,121,307, issued Oct. 24, 1978, which utilizes suction within the gutter trough.
Specifically, Patterson '307 provides an open gutter conduit or trough around the pool perimeter including a back wall, a bottom and an inner wall. A suction pipe extending around the perimeter of the pool at the bottom of the gutter trough and connected to the suction side of a pump for positive withdrawal of water from the gutter trough. In the embodiment shown in FIG. 2 of Patterson, the gutter trough is completely open although a grate or screen may be conveniently employed across the top to prevent possible plugging of the suction pipe holes by debris. In this gutter design, a continuous flow of water either through the skimmers or over the lip of the gutter conduit maintains a level of water in the gutter above the holes in the suction pipe to maintain a continuous and positive flow of water from the gutter conduit to the pool filter. The use of suction evacuation of water provides assurance of sufficient gutter capacity to accommodate even the greatest conditions of activity in the pool while avoiding flooding of the gutter. Further, it avoids the necessity of water traveling from remote locations via the gutter to the filter, but rather effects the removal of the water directly from the gutter from locations spaced around the pool. In operation, the water from the pool flows into the gutter continuously through the skimmer openings or over the top of the inner gutter wall in the case of surges from pool activity. In any event, the float automatically operates to provide assurance that al all times the passageways in the tube are covered with water. When so covered with water, a suction pipe withdrawing water from the tube will substantially uniformly draw water out of the gutter at all locations around the perimeter of the pool. Thus, the combination of the automatic float-controlled skimmer maintaining a proper level of water in the gutter and the suction pipe around the perimeter of the pool provides for continuous evacuation of the water from all parts of the gutter without cavitation of the pump and without gravity flow.
While the approaches taken in Odgen '397, Patterson '856, and Patterson '307 may be adequate in each perimeter skimming gutter and retaining wall disclosed therein, a need remains for still yet another efficient and cost effective approach for increasing water flow from the gutter trough to the filtration and circular system, particularly for use in the perimeter skimming gutter and retaining walls disclosed in the numerous patents to Baker discussed above.